Re: Engines CAN jettison (Was Rear engined aircraft. (727 DC9 MD80) )

From:         bradg@io.org (Brad Gillies)
Organization: Internex Online
Date:         03 Jan 95 01:40:40 
References:   1 2
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In article <airliners.1994.1787@ohare.Chicago.COM> T.E.Thacker.Junior@lesueloc.com writes:
>  The pilots can't purposely select to jettison an engine but they *CAN*
>be jettisoned:

>(1) They are designed in a ditching situation to shear off and flip over
>    the top of the wing rather than dig into the water & pull the wing off.

I will have to disagree with your first point.  Yes engines are designed to 
detach in such a manner as to "fly" over the wing but this would only happen 
with the engine still developing thrust and the aircraft must be in the air or 
on its wheels.  In a ditching situation the forces acting on the engine are 
such that the engine pylon and everything will just get ripped of by the 
ground or water or whatever.  Think of where the engine and ground will 
contact then work out where all of the forces are going to act, there is no 
way the engine will go over the wing in a ditching situation.
Brad
AME,A&P